Optical disc-shaped recording medium recording device and method for setting illumination power thereof

Abstract

A driving device and a calibration method for an ablation write-once type optical disc in which the recording light volume can be calibrated accurately without using an over-power for positively recording data on the ablation write-once type optical disc. A playback output by an optical head 3 for recording/reproducing data by scanning an ablation write-once type optical disc 1 with a laser light beam is supplied to an optimum recording light volume decision unit 4. A light recording data controller 6 controls a laser driving controller 5 for controlling the laser light volume of an optical head 3 for recording two different recording patterns with different repetition periods with various recording light volumes. The optimum recording light volume decision unit 4 detects the asymmetry amount from the playback outputs of the two different recording patterns and determines an optimum recording light volume of the ablation write-once type optical disc 1 based on the asymmetry amounts at the various recording light volumes.

What is claimed is: 
     
       1. A recording device for recording data on a disc-shaped optical recording medium by illuminating a recording light beam thereon, comprising: rotational driving means for running the disc-shaped optical recording medium in rotation;   pattern generating means for generating a first pattern having a first period and a second pattern having a second period longer than said first period;   recording light beam illuminating means for illuminating a recording light beam corresponding to said first pattern and another recording light beam corresponding to said second pattern for recording a first mark associated with the first pattern and a second pattern associated with the second pattern;   movement means for said recording light beam illuminating means for moving said recording light beam illuminating means to a desired position along the radius of said disc-shaped optical recording medium;   playback signal outputting means for illuminating a playback light beam on said first and second marks for reproducing a playback signal based on the reflected light beam of a playback light beam from said disc-shaped optical recording medium;   asymmetry amount calculating means for calculating the asymmetry amount based on an amplitude level of the playback signal derived from said first mark and an amplitude level of the playback signal derived from said second mark; and   illumination power setting means for setting the illuminating power of said recording light beam illuminating means based on said asymmetry amount.   
     
     
       2. The recording device for recording data on an optical recording medium as claimed in claim 1 wherein said asymmetry calculating means includes envelope detection means for detecting an amplitude level of upper and lower envelopes of said playback signal outputted by said playback signal outputting means;   calculation means for calculating said asymmetry amount by an equation (b-a)c+(constant) wherein a is an average amplitude level of amplitude levels of an upper envelope and lower level of the playback signal derived from said first mark;   b is an average amplitude level of amplitude levels of the upper and lower envelopes of the playback signal derived from said second mark; and   c is a maximum amplitude level of a playback signal as found by the difference in amplitude level between the upper and lower envelopes of the playback signal derived from said second mark.     
     
     
       3. The recording device for recording data on an optical recording medium as claimed in claim 2 further comprising: memory means for storage of a first maximum amplitude level as found by a difference in amplitude level between an upper envelope and a lower envelope of the playback signal derived from said second mark recorded with the minimum illumination power for which a bit error rate of the playback signal outputted by the playback signal outputting means becomes not higher than a pre-set value; and   comparator means for comparing said first maximum amplitude level and a second maximum amplitude level as found by a difference in amplitude level between an upper envelope and a lower envelope of a playback signal derived from the second mark actually outputted by said playback signal outputting means;   said illumination power setting means raising the illumination power when the second maximum amplitude level is judged by said comparator means to be smaller than said first maximum amplitude level.   
     
     
       4. The recording device for recording data on an optical recording medium as claimed in claim 1 wherein said first pattern is a repetition pattern of a period 2T equal to twice the period of a channel clock for data recording and wherein said second pattern is a repetition pattern of a period 6Y equal to six times the period of said channel clock. 
     
     
       5. The recording device for recording data on an optical recording medium as claimed in claim 1 wherein said optical recording medium is an ablation write-once optical disc. 
     
     
       6. The recording device for recording data on an optical recording medium as claimed in claim 1 further comprising: memory means for storage of a first asymmetry amount of a playback signal derived from first and second marks actually outputted by said playback signal outputting means and said first asymmetry amount; and   comparator means for comparing said first asymmetry amount and a second asymmetry amount of the playback signal derived from said first and second marks and which is actually outputted by said playback signal outputting means;   said illumination power setting means raising the illumination power when the second asymmetry is judged by said comparator means to be smaller than said first asymmetry.   
     
     
       7. The recording device for recording data on an optical recording medium as claimed in claim 1 wherein said recording illumination means includes servo means for illuminating said recording light beam at a pre-set focus or position on said disc-shaped recording medium; said recording device further comprising: memory means for storage of a first asymmetry amount of the playback signal derived from said first and second marks recorded with the maximum illuminating power recording light beam for which the servo means is not stable;   comparator means for comparing said first asymmetry amount and a second asymmetry amount of the playback signal derived from said first and second marks actually outputted by said playback signal outputting means; and   control means for controlling said recording power illuminating means so as not to illuminate the recording light beam if the second asymmetry is judged by said comparator means to be larger than said first asymmetry.   
     
     
       8. The recording device for recording data on an optical recording medium as claimed in claim 1 further comprising: control means for causing said illumination power setting means to set a plurality of different illumination powers and for causing said recording light beam illumination means to illuminate recording light beams corresponding to said first and second patterns with said illumination powers on said disc-shaped recording medium for recording first and second marks corresponding to said plural illumination powers on said disc-shaped recording medium;   memory means for storing a first asymmetry amount of a playback signal derived from said first and second marks recorded with a recording light beam of the optimum illumination power; and   optimum illumination power calculating means for generating an approximate quadratic curve based on said plural different illumination power values and plural asymmetry amounts calculated from an amplitude level of the playback signal based on said plural first and second marks and for calculating an optimum illumination power corresponding to said asymmetry amount from said quadratic curve.   
     
     
       9. A method for setting an illumination power for a disc-shaped optical recording medium configured for recording data by illuminating a recording light beam on said disc-shaped optical recording medium, comprising: a rotationally driving step of rotationally driving the disc-shaped optical recording medium;   a pattern generating step of generating a first pattern having a first period and a second pattern having a second period longer than said first period;   a recording light beam illuminating step of illuminating recording light beams corresponding to said first pattern and said second pattern for recording the first mark corresponding to said first pattern and the second mark corresponding to said first pattern on said disc-shaped optical recording medium;   a servo step of performing control for illuminating said recording light beam at a pre-set focus or position on said disc-shaped optical recording medium;   a movement step of moving said recording light beam illuminating means to a desired radial position of the disc-shaped optical recording medium;   a playback signal outputting step of illuminating a playback light beam on said first and second marks for outputting a playback signal based on the reflected light beam of the playback light beam from said disc-shaped optical recording medium;   an asymmetry amount calculating step of calculating an asymmetry amount based on the amplitude level of the playback signal derived from said first mark and the amplitude level of the playback signal derived from said second mark; and   an illuminating power setting step of setting an illuminating power of said recording light beam illumination means based on said asymmetry amount.   
     
     
       10. The illumination power setting method as claimed in claim 9 further comprising: a first storage step of storage of the first asymmetry amount of the playback signal derived from the first and second marks recorded with the recording light beam of the minimum illumination power for which a bit error rate of a playback signal outputted by said playback signal outputting means becomes not larger than a pre-set value;   a first comparison step of comparing said first asymmetry amount to the second asymmetry amount of the playback signal derived from said first and second marks actually outputted by said playback signal outputting means;   a step of raising the illumination power when said first comparison step finds the second asymmetry to be smaller than said first asymmetry;   a recording step of illuminating on said disc-shaped recording medium recording light beams corresponding to said first pattern or said second pattern with plural different illuminating power values for recording on said disc-shaped recording medium plural first and second marks corresponding to said plural illuminating powers;   a second storage step of storing a third asymmetry amount of the playback signal derived from the first and second marks recorded with a recording light beam of an optimum illuminating power;   an optimum illumination power calculating step of generating an approximate quadratic curve based on plural asymmetry amounts calculated from the amplitude level of the playback signal derived from said plural different illuminating powers and said plural first and second marks and for calculating an optimum illumination power corresponding to said third asymmetry amount from said quadratic curve;   a third storage step for storage of a fourth asymmetry amount of the playback signal derived from said first and second marks recorded with the maximum illuminating power recording light beam for which the servo means is not stable;   a second comparison step for comparing said fourth asymmetry amount and a fifth asymmetry amount of the playback signal derived from said first and second marks actually outputted by said playback signal outputting means; and   a control step for controlling said recording power illuminating means so as not to illuminate the recording light beam if the fifth asymmetry is judged by said second comparison step to be larger than said fourth asymmetry.   
     
     
       11. The illumination power setting method as claimed in claim 10 wherein said asymmetry calculating step includes envelope detection means for detecting an amplitude level of upper and lower envelopes of said playback signal outputted by said playback signal outputting means;   calculation means for calculating said asymmetry amount by an equation (b-a)c+(constant) wherein a is an average amplitude level of amplitude levels of an upper envelope and lower envelope of the playback signal derived from said first mark;   b is an average amplitude level of amplitude levels of the upper and lower envelopes of the playback signal derived from said second mark; and   c is a maximum amplitude level of a playback signal as found by the difference in amplitude level between the upper and lower envelopes of the playback signal derived from said second mark.     
     
     
       12. The illumination power setting method as claimed in claim 11 further comprising: a fourth storage step of storage of a first maximum amplitude level as found by the difference in amplitude level between the upper and lower envelopes of the playback signal derived from the second mark recorded with the minimum illumination power for which the bit error rate of the playback signal becomes not larger than a pre-set amount;   a third comparison step for comparing said first maximum amplitude level and a second maximum amplitude level as found by the difference in amplitude level between upper and lower envelopes of the actually outputted playback signal derived from the first and second marks; and   a step of raising the illumination power if said second maximum amplitude level is found to be smaller than said first maximum amplitude level.   
     
     
       13. The illumination power setting method as claimed in claim 12 wherein said first pattern is a repetitive pattern of a period 2T equal to twice the period of the channel clocks used in recording data;   said second pattern being a repetitive pattern of a period 6T equal to six times the period of said channel clocks.   
     
     
       14. The illumination power setting method as claimed in claim 12 wherein said disc-shaped optical recording medium is an ablation write-once type optical disc.